This research proposes to evaluate the role of glycerol as a feedback signal in the regulatory systems controlling food intake and body weight in the rat. In previous work I have shown that glycerol when infused slowly into the third ventricle of the rat causes a dose related reduction in body weight and food intake. Preliminary studies indicate that this effect is not specific to glycerol. Consequently substances which can be metabolized by the brain such as propylene glycol, glucose, fructose, and beta-hydroxybutyrate and substances which cannot such as 2-deoxy-D-glucose will be infused continuously into the third ventricle of the brain of the rat to determine the range of substances which can cause rats to regulate their body weight at lower than normal levels.